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FAQs on the Killifishes

Related Articles: Killifishes: Part 1 by Dr. Robert J. Goldstein, Killifishes, Part II- The Nothobranchius Family  by Robert J. Goldstein, Ph.D, Cyprinodontid Fishes, Aplocheilids, Rivuline FishesAphanius: European Killifish for Ambitious Aquarists by Matt Ford,

Related FAQs: Pupfishes, Aplocheilid Fishes,

Pachypanchax omalonotus playing dead 4-12-13
Bob and Neale - Have either of you ever heard of a killifish playing dead?
<Nope, not I.>
I found the smaller of my pair of Pachypanchax omalonotus upside down and leaning against a clump of java moss.  I reached into the tank with a plastic planted tank tool to tap the end of her caudal fin.
Before I could touch her, she immediately righted herself, darted around the tank for a few seconds, then disappeared into the cave I gave her to hide from the larger fish--an inverted coconut shell with an access hole.
She is behaving and eating normally today. No sign of any illness or a repeat of the behavior.  I've never observed this kind of behavior before, so I decided to send this as a query to share it.
<Means nothing to me… but could possibly be a constipation issue, so do try offering something high-fibre, like Daphnia, to see if that helps. Otherwise do try posting on a Killifish forum… there are several, including national ones for the US and elsewhere. Failing these, the Killifish subsection on AquaticQuotient.com is a good place to meet with expert killifish keepers.>
Rick
<Cheers, Neale.>

Strange pH and Snail-killing Killifish?  9/30/11
Hi crew,
I've been in touch with Neale (who's been MOST helpful) on and off regarding a new 4' x 1.5' x 1.5', 220L tank that has no lights and is sitting next to a window (no direct sunlight) with Val, Indian Fern/Watersprite, Java moss and fern growing very nicely in the 2.5 weeks it's been set up.
<Sounds nice.>
The filter was cycled in 10 days with pre-seeded media from an old bio-filter. 6 Melanotaenia praecox and 1 Aplocheilus Lineatus were added 4 days ago from my 60L home tank (they'd been in that tank 4 months or so).
Tank vitals today are:
Temp: 28 deg C
Ph : 7.4 (currently)
Ammonia: 0 ppm
Nitrite: 0 ppm
Nitrate: 5-10 ppm (colour is between two on the chart)
GH: 4 deg.s
I have 2 questions if that's O.K.?
1) The pH of the water coming out of the tap is 7.0. Last week the pH was around this, but has been steadily rising since, until the last 3 days when the pH has been stable at or close to 7.4. In the tank is gravel, some small granite rocks (with java moss anchored to them) and river stones, 2 terra cotta pots and some bogwood/roots (as well and the plants and fish).
Do you have any idea what might be causing the pH to rise?
<Photosynthesis and biological decay. Providing the pH doesn't vary wildly, like from 7 to 8.5 and back again each day, don't worry too much. It's perfectly normal for pH to change slightly in any aquarium, and if animals and plants seem happy, and you keep up with weekly water changes, don't worry. If you want, use a pH buffer, but really, there's little need in a well-maintained, moderately-stocked aquarium.>
2) I had A LOT of baby tadpole snails and a few baby Ramshorn snails in the tank (piggy-backed in on the plants) until yesterday, when only a few (at most) remained. The fish (as stated) went in 4 days ago. Is it likely that the killifish (or one of the rainbowfish) took a liking to escargot?
<Possibly, but I'm not aware of a snail-eating killifish!>
Cheers, thanks a lot and awesome website as always,
Duncan
<Cheers, Neale.>
Re: Strange pH and Snail-killing Killifish - add on stocking questions    10/1/11

Thanks a lot Neale - good stuff.
<Glad to help.>
Definitely no snails at all now - something got to 'em!!
<OK.>
Of course, sending my previous email and reading your response has prompted a few more questions - hope you don't mind?!?!
Is it strange that my water should be so soft, yet have a pH of 7.4?
<No, not that strange. While pH and hardness are connected, the connection is not as clear-cut as beginners suppose. Carbonate hardness is the stuff that affects pH, and if you have low general hardness but high carbonate hardness, your test kit might tell you have both soft water and an alkaline pH.>
Next. After what I hope is some decent thought and planning, I intend to stock the tank as follows. Each new set of fish will spend two weeks in quarantine (60L/15g tank) and will be introduced in the order as listed. Please let me know if I'm off the mark with any of these, their order, or over-stocked when I'm theoretically done. Of course 6 Melanotaenia praecox and 1 Aplocheilus Lineatus already live in the tank, plus my tank particulars can be found in the history to this email. Filtering is handled by an Eheim 2215 canister with just shy of 3x turnover per hour (a bit on the low side I realise, but the current seems pretty scary, even put through the spray bar).
10x Hyphessobrycon pulchripinnis - currently in quarantine and might add up to 5 more depending on how they go/stocking levels.
<A nice species. Not the hardiest tetra in the trade, and a bit bland under mediocre conditions, but an excellent species for soft, well-planted tanks. Blackwater extract makes all the difference when it comes to colouration, but failing that, shady conditions and a dark substrate are what you want.>
3x Crossocheilus siamensis - amazingly a LFS here has the real deal (based on the WWM article) for SG$2 each. Get 'em while they're hot (and available!). Will putting these 3 in a 60L quarantine tank for 2 weeks cause WW3 to break out? I'm not sure how else to quarantine them given my facilities'¦
<These are schooling fish in the wild, and while a trio is a gamble, you might be lucky. They're far, FAR less belligerent than the look-alike Flying Foxes and various Garra species.>
2 or 4x Trichogaster leeri or Trichogaster fasciata (1:1 male to female ratio) - would prefer fasciata, but haven't seen them in a LFS in Singapore yet :-(
<T. leeri is generally a good fish, and if anything, T. microlepis even better, despite being a shade larger.>
1x Ctenopoma acutirostre - will this munch the Lemon tetras? The tetras are almost the size of the Dwarf Neon Rainbows.
<Potentially a threat, yes, but does depend on their size. If reared together from young and trained to take alternative foods, shouldn't be too much of a risk. On the other hand, throw some adults in there, and yes, they'll view small tetras as dinner.>
2x Pelvivachromis pulcher (1m, 1f). Would love these, but not sure if they'll work, esp. with the Anabantoids and SAEs, plus I haven't seen them in any LFS here in Singapore yet. Maybe could order them especially'¦
<Could work well. Will breed all the time though, which gets annoying. A single female might be just as fun.>
That's my lot - thanks for making it this far! Sorry for the huge email.
Thanks so much crew/Neale, I think it's donation-time...
Cheers,
Duncan.
<Do feel free to buy us a beer at the front door of the website! It's been over 25 C here in England this week, a very unusual "Indian Summer" for this time of year. Cheers, Neale.>
Re: Strange pH and Snail-killing Killifish - add on stocking questions    10/2/11

Thanks so much Neale,
<You're welcome.>
With the SAEs, if they're schooling fish in the wild, should I be getting more than 3 for my tank? I based my number of three on the advice in Bob's article on SAEs on WWM, where he gives specific information about much space each individual requires.
<Well, schools of 6 or more don't need "gallons per fish" because they school together. Yes, there's a hierarchy, but the bigger the group, the less likely that problems will occur. It's really not much different to keeping things like Discus or Angels. On the other hand, in smaller groups the dominant fish is prone to bullying the weaker ones. Complicating matters is the wide availability of non-schooling, distinctly territorial look-alike species such as Garra cambodgiensis and the Flying Fox, both of which are best kept singly. I have a single Garra cambodgiensis, and it's an excellent algae eater as well as an entertaining fish, but it throws its weight around at times, chasing loaches and other bottom dwellers.>
Also, regarding the possible Krib pair, I was thinking that the Killifish and Spotted Ctenopoma would eat most of the parents' fry, despite their best efforts at defense.
<A pair of Kribs will beat even adult Ctenopoma acutirostre into submission. Do not underestimate the strength of these little cichlids!
What they lack in sheer size they make up for in tenacity and teamwork. In any event, Ctenopoma acutirostre feed primarily at the surface, and in the wild mostly stuff like mosquito larvae as well as, I dare say, the occasional small fish. In terms of behaviour they are extremely similar to South American Angelfish, and I'd argue they're African fish occupying much the same ecological niche.>
Being a classroom tank where I teach, I was hoping to demonstrate some breeding behaviour to the kids. Would this be overly stressful/cruel to the Krib adults, or should I just give any fry away to a trusted LFS instead (assuming I get a male Krib to go with the female)?
<The Kribs will protect their fry extremely well for the first 2-3 weeks, after which point they lose interest and the fry go off and fend for themselves. Whether the other fish cull the fry then I cannot say; but possibly. There's some recent scientific research that suggests cichlids actually exhibit a true weaning behaviour similar to that of mammals and birds where the parents steadily make life more difficult for the offspring so that their offspring eventually choose to go off on their own. While tangential to your question, this does highlight the value of the Cichlidae as models for understanding "higher" animal behaviours within the confines of labs or classrooms. It turns out that cichlids are every bit as sophisticated as mammals and birds, and that fish aren't "lower" animals in any objective sense.>
Thanks crew/Neale, I'll stop asking questions eventually!
Duncan.
<Cheers, Neale.>

Killie not eating (Pachypanchax playfairi; diet, introduction)   3/14/11
Hi Crew,
<Salve!>
I picked up a pair of Pachypanchax playfairi at auction on Saturday.
<A fine species. I have a female in one of my community tanks.>
I have them housed temporarily in a filtered 2.5 gallon tank with a clump of java moss inside.
<Will need more than this.>
At the advice of an expert (PhD specialist in Pachypanchax) they will be going into a 10-gallon heavily planted tank in a week or two.
<Yes. They can get fairly big, 10 cm/4 inches, though 8 cm/3 inches seems typical, so I'd give them the longest possible tank. Water depth relatively unimportant. Do review water chemistry, temperature. Avoid excessively warm or soft water.>
In the mean time, these fish are not eating, and I have no idea why. I have given frozen bloodworm, earthworm flake, frozen mysis shrimp, and frozen brine shrimp. The female snatched and immediately spit out one of the bloodworms on Sunday morning and neither fish has shown any interest whatsoever in food since then.
<May be stressed. Too small a tank, perhaps. Mine showed little interest in food for a couple days. They are fairly shy fish, especially in bright light or strong water currents. A few appropriate dither fish may help.
Mine live with Celebes halfbeaks, which are very much more greedy, but because they feed from the surface, don't compete too strongly once food falls down the water column. Small chunks of prawn seem to be most enticing, but do also try earthworms, daphnia and brine shrimp.>
I even dropped an Endler fry into the tank and the fry is doing all of the eating. The Killies ignore the fry.
<Not for long. They are extremely predatory. If hungry, will eat fry readily. No need to feed so long as they're ignoring guppy fry.>
Any suggestions, or are these fish maybe still recovering from the stress of being in a bag on a table all day during the convention?
Rick
<Cheers, Neale.>
Re: Killie not eating (Pachypanchax playfairi; diet, introduction)   3/14/11
Thanks Neale, They will move into the bigger tank as soon as I am through moving furniture around like one of those number slide games. I have 4 tanks that will be set up soon, so these guys will have the space they need shortly. 2.5 gallons is better than a small plastic bag.
<Indeed so.>
By the way, I couldn't find any desert gobies except on Aquabid, where competition was pretty fierce.
<It is odd that these Desert Gobies are so scarce/expensive. They aren't difficult to keep or breed.>
I bought instead 6 bumblebee gobies. No idea which of the 10 or 11 species these guys represent as the breeder did not tell the retailer. The breeder may not even know. But, they are doing great.
<Yes. They aren't difficult to keep, though they can be fussy about food.
As I've mentioned here at WWM many times, brackish water isn't essential, though it can be useful if you want to maintain brine shrimp in the water for long periods so your BBGs can feed at their own pace.>
Rick
<Cheers, Neale.>
Updates  3/26/11

Neale,
<Rick,>
Yesterday I moved my Pachypanchax playfairii pair to their 10-gallon permanent home. They are much happier there and both male and female are eating well.
<Cool.>
The Endler fry I added to the smaller tank finally vanished. Interestingly, though, I added a fry to my brackish bumblebee goby tank at the same time. Not only is that fry tolerating the brackish water,
<Which they will do, easily. Guppies and Endler's have been acclimated to full-marine conditions.>
it is also too fast for the gobies to catch. He'll be moving into the Endler fry-rearing tank I'm currently leak-testing.
Oh, and for Bob: I let that Costia-stricken tank run empty for over 6 weeks and finally restocked with a new pair of nickle-sized angelfish (P. scalare) a week ago. I bought from a local breeder this time. Much better experience.
Rick
<Sounds like you're on the right track. Good luck, Neale.>

compatibility... info.    12/16/10
Crew,
<Rick>
I have a 20-gallon tall that I'm looking to fill. I'm considering a pair of (freshwater) angelfish and a pair of Killies or two different species pair of Killies
<What species?>
in a planted tank, but I'm not sure about compatibility between angels and Killies.
<... again>
I may add a pair of Siamese algae eaters also, and that pretty much tops out the bio-load for that size tank.
One other question. Although I don't plan to use it, this tank currently has an undergravel filter. I'm curious whether there is still a place in the hobby for undergravel filtration.
<See WWM re... http://wetwebmedia.com/FWSubWebIndex/fwugfiltfaqs.htm
and the linked files above. Bob Fenner>
--
Rick
Re: compatibility... reading    12/16/10
Undecided on the Killie species. Depends largely on what is available here. I'm open to suggestions since I've never kept Killies before.
<? Do a bit of reading, investigating before purchasing... Many species of Killifish are difficult to keep except under special conditions (i.e. not w/ Pterophyllum); some are too retiring. B>
Re: compatibility - 12/16/10

Have been reading on Killies, but there is a lot out there. I think I need to find a local AKA member instead of pestering you guys.
<Or a good book perhaps>
By the way, my new Endler's are doing great. Different personality than mollies but still fun.
Rick
<Ah good. B>

Floating at the surface. Beh.  - 10/10/10
Dear Crew,
Just got two golden wonder Killies (male and female). While in bag they would float very close to the surface then stopped. After I acclimated them in the tank (put the bag in aquarium 15 to 20 min. later put some aquarium water, waited another 10 min. put more aquarium water then let another 15 min. before letting go was this correct?). They then began to float at the top again. Is this "natural after acclimation" activity or did I do something wrong? If I did something wrong, is there a way to help them return to normal?
<Golden Wonder Killifish -- Aplocheilus lineatus -- are surface swimmers. It is completely normal for them to swim right at the very top of the tank, ideally under some floating plants and where the water current is gentle. Couple of warnings though. This species is territorial, so allow a good square foot or so of space per specimen. Secondly, they are incredibly predatory; at up to 10 cm/4 inches long these fish can, will swallow tankmates as large as Danios. Oh, and they jump; keep the tank covered!
Anyway, next time you acclimate new fish to your tank, don't float the bag. Empty the bag into a bucket. Add a cup of water from the aquarium every 5-10 minutes until the bucket is filled up. Put a towel over the bucket in between times to keep the fish from jumping out. After 30-60 minutes net out the fish and release it into the tank. This way you minimise contaminating your aquarium with water from the pet shop. That pet shop water will likely have lots of ammonia and can also carry various parasites. Cheers, Neale.>
Re: Floating at the surface. - 10/10/10
Dear Neale,
Thank you ever so. Though I do have one more question it appears, when I saw them at my LFS, they were in a pair. They still are (following each other) but the female tends to nip at the male and seem to hit him with her tail is this natural also?
Thanks
<Could very easily be aggression. These fish aren't nippy, but they will fight. Provided both specimens otherwise seem happy, and better still, if they're both eating, I wouldn't worry too much. They can form pairs, and hopefully yours are behaving as such, but they aren't like cichlids in the sense of having a pair bond. With that said, male/female duos generally settle down quite well. Cheers, Neale.>

Mangrove killifish, sel.   3/1/10
hello,
thanks for the great website.
Is there any way you can give me a link to someone who sells mangrove killifish? I have a mangrove setup with mudskippers & other brackish water critters. thanks so much
ray
<Like most of the brackish water killifish, the Mangrove Killifish, Kryptolebias marmoratus, is a species you usually have to collect yourself (assuming it is legal to do so). If that isn't an option, then your best bet is to contact a biological supply company in a part of the world where this fish is found (Google "biological supply" and you'll find lots of such companies). Such places routinely sell other killifish species widely used in labs, including the brackish and marine species, though I will caution you that many of the Cyprinodon and some of the Fundulus species are far from gentle community fish. If that isn't an option, then you'll have to concentrate on alternative species available in the tropical fish trade, such as the Diamond Killifish (Adinia xenica) or perhaps the more unusual livebearers like Wrestling Halfbeaks (Dermogenys spp.) and Swamp Guppies (Micropoecilia picta). Cheers, Neale.>

Clown Killi Temperature   2/25/09 I am planning a small planted tank with a group of Pseudepiplatys annulatus. I've done some research and have some questions about keeping them in an unheated tank. I've read that keeping them in a "room temperature" environment could prolong their lifespan. I also am I bit attached to the idea of keeping the tank as low-tech as possible. Despite some various forum posts throughout the web whose authors demonstrate success with these killies at low temperatures, the majority of references I can find including Fishbase suggest a much higher temperature. I was hoping to get an opinion from the people I trust most at WetWeb. Thanks in advance, Matt <Does depend on room temperature in your part of the world! Here in the UK, that would be too cold. this time of year anyway. But yes, keeping annual killifish slightly cooler than the wild can extend their lives. But we're talking a degree or two; 23 C (73 F) would be ideal. Any colder and you're running the risk of health problems. Cheers, Neale.>

Killies Fish help 2/18/08 Hi Guys! My question is in regards to Killifish, particularly "golden wonders" in my 30 gal tank. <These are an artificial morph of Aplocheilus lineatus, and doing your searches online and in books by the Latin name will be rewarding.> They are the only top fish, with a few other lazy, friendly mid & bottom fish. I've read the appropriate section to find a bit of insight, but I need a better confirmation of my concerns regarding color changing. I have 2 golden wonder killi's <No need for the apostrophe!> fish who have both gotten along just fine for 4 months swimming together like pals. About 3 days ago I noticed one being chased aggressively by the other, and the one that was being chased changed color to almost completely black, with a color similar to that of ammonia burns with deep black veiny lines. So before I knew what I was dealing with, I put the now black killie in a hospital tank, to isolate him from the other, and to make sure he healed if the black was indeed actual "scabs" from being attacked. After 3 days of quarantine, he slowly got 80% of his normal color back. <OK. Fish typically turn dark when stressed. Aplocheilus lineatus is a territorial fish, and in small tanks it is best to keep just the one. This is especially true if there is only a limited amount of floating plant material. Aplocheilus lineatus squabble over the best places to "lurk".> I also read that community fish that are aggressive sometimes do better in odd numbered groups. <Isn't as simple as this. Tiger Barbs, for example, are better in groups because they need a certain number of individuals in their social group. But other fish will simply fight if kept cramped, until you end up with just one dominant fish and a bunch of dead/stressed subdominant fish. So as ever, you need to read up on the specific behaviour of the fish in question. In your case, no, this isn't likely to work.> So, I bought 1 more killie, a little larger to help keep the peace between the new "Threes Company". <Doesn't work like this. Fish don't "keep the peace". They aren't a branch of the United Nations. Peace breaks out when all the fish accept their position in the social hierarchy and no longer view one another as threats and/or rivals.> The one that was originally chased & black is still chased & black. The new big guy and the smaller aggressor seem to have "stand offs", ironically the big guy loses & turns black too. However I did see all 3 turn black temporarily & all hide from each other after a 3 way "stand off" once. <I bet.> So I guess my question is that by turning black, are they showing signs of submission, or are they actually injured & internally bleeding? <Neither; dark colours mean "I'm unhappy".> If I quarantine the main aggressor in a hospital tank "small type that sits in the main tank like a hatchery" for a few days, would that calm him down? <The only way these fish "calm down" is when they are kept in a tank with sufficient surface area and an equitable distribution of hiding places at the top of the tank. In a 30 gallon tank, my guess would be you could keep no more than two males, and even then if there were two clumps of floating plants, one at each end of the tank.> I know fish have the ability to learn somewhat, but how well can fish retain memory or how smart are they? Can they learn that aggressive behavior will end them up in isolation for a few days? <Fish can be plenty smart, but this no more affects their ability to get along with each other than it does with humans.> Ultimately I want to know why they are changing black, and if its a submissive/dominance problem, should I add 2 more killies for a total of 5 in the hopes that a larger group will calm this aggressive booger down? Thanks!!! Tim P. <For a start establish whether you have males or females. Females are less brightly coloured, and should always outnumber the males. One of the most common mistakes less experienced aquarists make is to just buy males, because they're more colourful. This is very bad. The males fight. Females should outnumber males 2 to 1, and under such circumstances, male killifish will generally concentrate on the females rather than rival males. Cheers, Neale.>

Nothobranchius community   1/19/08 Mr. Monks <It's actually Dr. Monks, but please call me "Neale" or "Hey, you there". Everyone else does.> Thank you so much for you quick response and knowledgeable advice. I've decided to heed your warnings and adjust my stock list as follows. 6x Swartz's Cory cats 2x (M+F) Patrizi killifish Nothobranchius patrizi I like their color more. 1x Siamese algae eater I have omitted the snails, the Bettas and the dwarf Gourami. <All sounds fine, although I am very slightly concerned that an SAE might be a bit much for Nothobranchius; these latter killifish are fairly territorial and plucky in their way, but I'm not sure how they'd react to a big, fast-moving Cyprinid darting about the tank.> I have also decided on going with a smaller Eheim canister filter. The 2229 model flows at 280gph. I was thinking along the lines of 150gph because killifish do come from more calm waters. <True. But do be careful: reducing the flow of water also means reducing the quality of the filtration.> As for the Cichlid it was a Frontosa Cichlid, after reading their required water conditions I am shocked the former owner kept it alive. I observed it actually nip at the barb and the Pleco. <Cyphotilapia frontosa is a deep water predator. Although a peaceful, docile cichlid it is predatory, and can't be considered a "good community fish" except with large species of fish. Beautiful fish though.> I also observed the barb nip at the Pleco. Good news with the barb and the Pleco a different local fish store has agreed to take them in and get them back to a healthy state. That store has earned my business. <Good news!> They will also order and quarantine any fish I want for up to a month. Would I still need to quarantine the fish they quarantined? <Probably not, assuming the fish were quarantined properly.> I have also decided to fish less cycle the tank with the new filter. <Wise.> Tons of plants will come in time after the system has matured and appropriate substrate, lights, yadda yadda are bought. I've always had bad "luck" with aquatic plants but with the knowledge I am obtaining on WWM I know I will be well armed with good "luck" this time around. <Almost all problems with plants come down to inadequate light; when given sufficient light plants usually adapt well to even the "wrong" water chemistry or substrate. Do bear in mind that the Amano-style planted tanks are somewhat incompatible with regular fishkeeping -- if you look at an Amano tank, it is always understocked and contains only tiny, non-messy, non-burrowing fish. Once you start getting things like catfish and medium-sized species of fish, you have to moderate your expectations from the plants a bit. For example, get robust species like Anubias and Java fern for "sculpting" the scenery, and fast-growing bushy things like Hygrophila for algae control.> Thank you again! Ed <Cheers, Neale.>

A little different... BR, FW, SW... Killifish... ID, sys. and Mollienesia comp.    12/5/07 Hello Bob, I happened to stumble across your web site and it just so happens, I have quite a few questions that I hope you can answer for me. I have a 55 Gal aquarium with Eheim and Skilter filters. I purchased the aquarium about 18 years ago. I had success with community setups for many years but some how lost interest in the hobby and just let everything go to pot. This summer I was collecting live bait from the lagoon in my back yard. The bait consisted of killies. I don't know the proper name for that species of fish but that is what we call them. Any how after the fishing trip was over I had about 12 killies left. My tank had a couple of tiger barbs and a couple of platys in it at that time. I decided to dump the kellies into the tank. About 8 of them survived. Since that time I have been adding water from the lagoon. Needless to say only the kellies remain in the tank. Yesterday my wife came home with 8 silver sail fin mollies. What a surprise. So now I would like to know what to do ? The PH was at 6.4. I know I will have to bring that up to about 7.2 but after that, I don't know. I would like to dedicate the tank to the mollies. Any suggestions would be greatly appreciated. Please keep in mind that although I have kept tropical's for many years, I have no knowledge of salinity factors or chemistry of any kind. Hoping to hear from you soon. Tony <Hello Tony. It's hard to give advice here without knowing the species of Killifish in question. Some are freshwater, some brackish water, and some marine. This is especially true in the US where killifish are ecologically very varied. I can't say I'm wild about the ethics of dumping a bunch of native fish into a community tank without first checking water chemistry and compatibility issues. If these killies are species of Fundulus for example, and the water from your lagoon was brackish, then the poor Tiger Barbs and Platies faced a miserable and slow death from aggression (from the Fundulus) and dehydration (from the salty water). No responsible aquarist would ever inflict this sort of slow, painful death on any animal. Your first job is to identify the killifish. Most of the larger, bait-sized North American (Fundulus and Cyprinodon spp.) species are somewhere on the spectrum of "nasty" and mixing them with fish as mild as Poecilia (Mollienesia) spp. would be incredibly cruel. Furthermore, you will need to ascertain the water chemistry requirements for the killifish in question. Mollies do best in hard, alkaline water ideally with salt added to around 25% normal marine salinity (~SG 1.005). Some killifish will thrive in such conditions, but others will not. My gut feeling is you won't be able to mix these two species. But if you want to send along a photo of the Killifish, perhaps someone here on the WWM crew might be able to identify the fish for you. Cheers, Neale.>

Re: A little different... Kill's fisches... sys.  12/7/07 Neale, <Tony,> Gee, I never thought of it that way. The killies are not at all aggressive. <You got lucky! The North American killifish include some VERY mean species when kept in confined spaces, as well as a number of species that need brackish or marine conditions to do well. This is why they're uncommon in the ornamental fish trade.> As a matter of fact they are quite community minded. They right now are swimming around with the mollies in perfect harmony. <Very good. They are fun fish to catch and watch. I thoroughly enjoy keeping coldwater fish, especially marines, but you do need to take care choosing what species to mix together.> I guess I did make a ass of myself by adding the killies to my tank and added to the lunacy by using the brackish water from the lagoon for water changes. I will be more dedicated to my aquarium now then I have ever been in the past. <Cool.> What test kits do I need to keep everything in order? <Baseline when keeping wild-caught fish would be salinity, carbonate hardness, and pH.> Thank you so much for the come back. I will not forget it. Tony <You're welcome.> P.S. I live in New Jersey if that will help you in any way to identify the killies. A friend told me that they were also called mummichugs. I will research to get the proper name for you. <Ah, Fundulus heteroclitus. One of the hardiest killifish. Able to tolerate anything from freshwater to hypersaline conditions around 3-4 times more saline than the sea. Also tolerant of water temperatures from freezing to over 30 degrees C. Optimal conditions would be moderately brackish water (say, SG 1.010) at 15-18 degrees C. Lots of carbonate hardness, ideally 10 degrees KH upwards. Good filtration would be beneficial, though it is a confirmed air-breather able to tolerate swampy conditions for extended periods. Will jump out of uncovered tanks. Unlike many other killies, this species is somewhat gregarious. That said, the males can be short-tempered towards one another when mature and fighting over females. Maximum size about 15 cm, though commonly smaller. An omnivore, feeding on algae, insect larvae, crustaceans, and small fish. Widely used as a laboratory animal and commercially handled as a bait fish, but not common in the aquarium hobby. Hope this helps, Neale.>  

ID this fish? -- 11/16/07 Hello Crew! Thanks in advance for reading this message. I was hoping one of you could help ID this fish. There are countless numbers of them living in a pond here in Central Florida. It's actually on a friend's property, but is stocked with local flora and fauna. So far I have been able to identify mosquitofish, least killifish, and rock bass of some sort living in there. Not sure how the bass got there, must have been via eggs stuck to the leaves of plants? <Possibly. Here in England we talk about eggs stuck to ducks' feet. More likely deliberately stocked.> In any case, there's one fish I cannot identify... In order to get a better look, I placed it in an aquarium. I apologize for the very poor quality of the photographs, but the LCD is cracked on my digital camera, so I cannot view the menu in order to adjust the settings. These three pictures were the best of several, believe it or not! They look a bit like golden wonder killifish without the fancy finnage - upturned mouths and slender bodies. The spangles on the side are iridescent as you can see, but the overall color is almost translucent as a juvenile. Adults seem to develop a more opaque greenish coloration throughout, and grow to...hmm, between two and three inches long, I believe. <They are definitely killifish. At first glance it looked to me like an Asian killi, such as the dwarf Panchax Aplocheilus parvus. It has the Panchax-shape about it. But as far as I know there aren't any Panchax established in the US. So anyway, identifying your fish still further is tricky for me because this isn't a group I'm expert with. So this is a process of elimination, and others may well have better ideas! They look too slender to be pupfish (family Cyprinodontidae) so my assumption is they're some sort of topminnow (Fundulidae), perhaps the Golden Topminnow (Fundulus chrysotus). Perhaps someone else here at WWM will have a better idea? In any case, looking at a handbook of Floridian fish under the Killifish section should help.> Thanks again! Have a great weekend. <Cheers, Neale.>

Killifish that lives up trees 11/8/07 And it's a brackish water species too, the trees in question being  mangroves!  http://www.dailymail.co.uk/pages/live/articles/news/news.html?  in_article_id=488193&in_page_id=1770 http://www.flmnh.ufl.edu/fish/Gallery/Descript/MangroveRivulus/ MangroveRivulus.html  Apparently their "gills are altered to retain water and nutrients,  while they excrete nitrogen waste through their skin" and breathe  air. Perhaps these killifish are on the way to evolving into a North  Atlantic mudskipper!> Cheers, Neale <Neat! Bob>

Killifish compatibility  9/3/07 Hi Crew, I have a 22gal community tank about 8 months old; ph 6.4-5, no nitrites, very soft water, Nitrates 25ppm, temp is 22C. I have a trio of Golden Wonder Killies in there at the moment along with Corys, 3 adult Kerri Danios, 2 Hillstream Loaches and a 'true' Flying Fox (I know this is a touch too cold for him, will he adapt okay? He's new!). I've purchased some Aphyosemion Australe eggs and hopefully will be able to hatch some so I can have a trio of those too. Will the Killies tolerate each other or fight? The Golden Wonders are still quite small and very peaceful at present, but I read somewhere that you shouldn't mix different species of Killifish? Thanks very much, Ruth <Hello Ruth. In a word, no, you can't mix Aphyosemion australe with Aplocheilus lineatus (which is what your Golden Wonder killies are). For a start, Aplocheilus lineatus will eat them. Aplocheilus lineatus is a voracious predator that feeds on insect larvae and small fish. Aplocheilus lineatus are also very territorial (especially the males) and being twice the size of the Aphyosemion australe, any fights could only have one outcome. Aplocheilus lineatus will get to about 10 cm, and are more than capable of eating danio-sized fishes, so that combination is a risky one. I'm a bit curious why you have very soft water. Neither of these killies really need that; my assumption is that for Aphyosemion australe slightly soft water (5-10 dH, pH 6-7) is what you need. Aplocheilus lineatus will adapt to almost anything, from quite soft through to brackish. The problem with very soft (< 5 dH) water is the lack of water chemistry stability so as a very broad rule, I tend to recommend keeping fish in only moderately soft water unless there's a specific need to do otherwise. Anyway, assuming your Flying Fox is Epalzeorhynchos kalopterus, then no, it really shouldn't be kept at 22C indefinitely. I'd bump the temperature to 24C. This should be acceptable to all your fish, especially if you ensure water circulation in the tank is good enough to transport oxygen all around the tank. The problem with too-cool water conditions is that the physiological processes in a fish are "geared" to work together at some specific temperature range. If too low, these don't work adequately, and things like digestion and immunity become "faulty". At the extreme, the fish becomes sick and dies. Hope this helps, Neale.>

Your photo of Fundulus parvipinnis  12/24/05 Hello Robert We never were introduced, but l dare to contact you because it appears that your photos of Fundulus parvipinnis are unique. <Interesting... am out in FLA for the week... do feel free to use any of my content for non-commercial purposes. Bob Fenner> I would like to have them for Killi-Data. Could you help, please ? If you wish, I'll give you all details (you may also visit the research website below). Merry Christmas and a Happy New Year ! Jean Visit Killi-Data website: www.killi-data.org Access to "guest" section simply with your e-mail Access to "member" section (database) after registration process in "guest" section To see an example of the database in "guest" section, click on SAMPLE Twice a year newsletters, plus Killiflashes immediately after important publications (new species!), upon free subscription. Dr Jean H. Huber, Ichtyologie, Museum national d'Histoire naturelle, Paris, France. Private address: 7, Boulevard Flandrin, 75116 Paris, France

Re: Your photo of Fundulus parvipinnis  12/30/2005 Hello Bob That would be a fine Christmas present ! Yes this is for research only... but since it is for scientific research and record I need high resolution pictures. If you are interested, you must send high resolution digitals by e-mail or slide duplicates to my private address. Then I know you need to trust me. All scientists in the US and many aquarists could support this. If you tell me some names you trust, I shall contact them so that they send you a testimony. Or if you know Tony Terceira, you should know that he already gave 60 pictures for the data base (which holds 1980). No emergency... enjoy FLA (Paris is cold and a icy cold period is to come on Tuesday) Jean <Tis chilly even in S. California. Please find the two pix I have attached. Cheers, Robare Fenner> Visit Killi-Data website: www.killi-data.org < http://www.killi-data.org> Access to "guest" section simply with your e-mail Access to "member" section (database) after registration process in "guest" section To see an example of the database in "guest" section, click on SAMPLE Twice a year newsletters, plus Killiflashes immediately after important publications (new species!), upon free subscription. Dr Jean H. Huber, Ichtyologie, Museum national d'Histoire naturelle, Paris, France.

Re: Your photo of Fundulus parvipinnis  12/30/2005 Great Robert They are perfect ! Many thanks ! Just 2 minor questions SIO2 is the male and SIO the female ? <Mmm, this would be my guess, yes> Do you know the collecting locality by chance ? <Almost certainly in Mission Bay, San Diego, California. I shot these pix at the Scripps/Birch Aquarium in La Jolla> I don' t know if you are a Killifish nut... would you like free membership and access to the database, as a "reward" ? If yes, you'll still have to do a small work : fill the registration form online (2 minutes, within the 'guest' section). <Appreciate your kind offer, but am a bit of a distance from reviewing the cyprinidontiform fishes... have some experience with the desert Pupfishes many years back... occasionally chat with friends... some even knew Jorgen Scheel...> Paris has been icy (below freezing), but now it is getting milder... and tomorrow anyway we'll be warmed by Champagne! <Heee!> Happy New Year ! Jean <Merci! And to you and yours. Bob Fenner>  

Help! Sick Killie - Combined Responses  11/14/05 I now have a female Golden Wonder killie with obvious dropsy. I had considered her to be pregnant for a little while, and was waiting for some sort of breeding behavior. Now of course, I'm smacking myself. She's stuck out of the crowd a little, lately, because she very suddenly developed a dark gray patch along her left side. It's proven difficult to get a picture of her, but if needed, I'll try again once I buy that hospital tank (or tanks) that I'm going out to buy in less than an hour.  I'll try to describe it: If you look at her left side, it looks like she's got the lower left corner of a rectangle on her. It starts in a straight line right behind her body cavity, from the dorsal to about 2/3's down, then a right angle turn leading straight to the tail, with that straight line intersecting the curve of the lower part of her body before it reaches the tail. That straight, bottom border is a stripe darker than the rest of it. I just made a (really awful) drawing, which I am attaching in lieu of a picture, to try to illustrate. She's had this patch for a little while, and I kept an eye on her. Her habits didn't seem to change any, inasmuch as the tank is still relatively new and I'm still getting used to their behaviours. She still fed enthusiastically, and I keep thinking I've seen her in breeding behaviour with one of the males, but I can't recall absolutely it was her. I don't know if the patch is related, but I'm writing on the off chance it is, and that it might be something recognizable. This morning, I came up one fish short, and found her hiding in a back corner, looking like a little fishy pinecone. Having scanned your site a bit in the last... what, week? Goodness... I realized I'd read something about the scales sticking out like that, and was able identify it as dropsy.  <Of numerous etiologies (causes)> <<Agreed.... perhaps bacterial, in this case, but in all honesty, no way to know from here.>> I'll be bringing home two small, basic <1 gallon betta tanks, and a small airstone. As your site suggests daily water changes, I figured I would transfer the killie from tank to tank each day instead of getting a filter, cleaning the just-used one and putting pre-treated, stabilized water in it (as best I can in a hurried setup). I found out when we were running from Hurricane Rita that our aquarium water stayed at a reasonable temperature, but I'll probably pick up thermometers too just in case, and add a small heater later if needed. Hmm. Probably some small hide-in-able thing, as well.  According to my test kit (Mardel Master Test Kit) my water is stable - ammonia and nitrite at 0, nitrate just below 40,  <Way too high...> low-level hard water (normal for the area,  <... and what sort of water does this species prefer?> and the store said they have the same), buffering on the low side of ideal, and pH perhaps on the low side as well. The thing I have been remiss in is water changes. That was something I learned rather late in the game, and I already had a gravel vac and a 10 or 15 gallon tank on my shopping list. All of the other fish appear to be fine, and were feeding well this morning. So, does this patch, or my lack of water changing, suggest any particular cause for the dropsy, or is it too vague to tell? <Like colors, "dropsy" is only a descriptive term... tells nothing re causes> With the medication and whatever food I can find (I think I read somewhere that Tetra medicated food is hard to get any more?),  <<There are more effective products available now - one from Jungle, one from.... Umm.... Aquarium Products, or something like that, which I haven't used. Also can find medicated foods at http://flguppiesplus.safeshopper.com/ .>> is my "hospital" setup sounding good (I hope, because as soon as I send this, I'm off to the store)? Assuming I pull the girl through, at what point can I consider her "cured" enough to go back into the main tank; conversely, if she gets worse, is there a visible point where I should consider a humane farewell?  <<This bit only you will be able to determine.... If the fish seems to be in considerable discomfort and you are quite confidant that she will be unrecoverable, you might consider this option. Again, only you can make this very subjective judgment call.>> And what other symptoms can I look for that may help diagnose the actual problem? *flapping arms* So many questions! Can Sabrina just come live with me?!? :-D <She didn't respond w/in a day... Will cc her here. Bob Fenner>  <<Didn't happen to read this one last night.... As for being a live-in, I'm pretty low-maintenance, but you've gotta have good avocados! I think I'll stick to my funky mountain home for now. -Sabrina>>

New community fish attacked...  10/2/05 We are new to having fish, but have spent a lot of time researching on the internet to be informed. Our tank has cycled and we added fish, been doing regular cleaning and water changes and things were going well until today. I tried to add new fish to a 36 gallon community tank and they were attacked. I have 1 golden wonder killie who grabbed the new harlequin rasbora and was swallowed him on down. We were able to net him up and he spit out the fish, but was severely damaged and had to be destroyed. The killie fish also took a big chunk out of the new zebra danio's tail as well. I'm not sure if he will make it either. <... you know that not all fish species, individuals are compatible> The new fish are smaller than the ones in the tank, but what I researched said they would all play well together. My three children watched this happen and are very upset by "big yellow" now. They want me to take him out of the tank. We have the 4 remaining rasbora fish in a net on the side. I'm not sure what to do. Should I go buy a separate enclosure to keep these small guys safe until they get bigger? Should I separate the golden wonder killie? <The latter. Best to remove period> We have 1 dwarf powder blue Gourami who is very friendly, 5 Scissortail rasboras, 5 red minor tetras, and the "killer yellow fish". They have been in there for a month now and are all bigger than the new ones we tried to add. We were trying to increase the zebra danios to 7, but who knows how many are left since I've been upstairs. Please help, by children are very upset! Thank you! Carol Thompson <I can imagine... do try to arrange for compatible tankmates... and remove the killifish. Bob Fenner>

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